Invercargill mayor Nobby Clark will be asked to resign at an upcoming extraordinary meeting following another code of conduct complaint.
The meeting on Friday has been called as a result of the complaint.
Clark is under fire for his behaviour at a United Fire Brigades' Association (UFBA) prizegiving dinner as a guest of honour.
In a March letter of complaint to the council, UFBA chief executive William Butzbach said the mayor articulated disturbing and offensive views at the event.
This was initially passed off as "banter", but when others challenged the mayor he threatened to talk about them on stage, Butzbach said.
He said Clark mocked, disrespected, degraded and offended its members, staff, and other guests by stating volunteer firefighters were second-class citizens, making personal attacks on the MC - including her appearance, competence and the fact she lived in Ponsonby - and wrongly implying the UFBA president and MC were having an affair.
Butzbach said everyone was horrified and appalled by the mayor's "hateful and disrespectful rhetoric" and many members and guests left the room in disgust.
A code of conduct complaint was lodged by council chief executive Michael Day on behalf of the UFBA.
Clark has since apologised in a letter to Butzbach, saying he was suffering from "brain fade" following open heart surgery. He also maintained some of his behaviour was not as described.
"For me, I felt terrible after the dinner and within a couple of days, and well before the complaint was lodged, I sought some specialist advice, as I do not normally present this way at public meetings," his letter said.
As a result of the investigation, Clark was found to be in breach of the council's code of conduct, with the matter to be considered by the council at the extraordinary meeting on Friday.
Councillor Ian Pottinger said the mayor's behaviour has been unacceptable.
"It's brought disrepute to Invercargill and no apology will fix that and that's why I will be asking for his resignation," he said.
"I can only ask, because council can't even by majority of vote sack a mayor. So you can only ask, but the reason is the only fix for what has happened is for him to resign - for the betterment of Invercargill."
Pottinger said there was "no place to hide" for each councillor.
"They will have to speak on Friday. As your job as a councillor you have to have an opinion on this, and you need to state it. Each councillor needs to think very carefully about what they're going to say tomorrow."
Pottinger said he had not spoken to Clark about his intentions.
In April, Pottinger and another councillor Ria Bond filed a code of conduct complaint against Clark after his appearance on Guy Williams' satirical news show New Zealand Today.
During his interview with Williams - described as "a train wreck" by one of his elected members - he defended previous instances where he has used the N-word and again repeated the slur.
Clark first courted controversy last year when he used the word at an Art Foundation event, supposedly to make a point around "tolerance" and "freedom of expression" within the art world.
He doubled-down on the matter during his appearance on the 21 March episode of New Zealand Today.
"If you had some rap music that come in, where every second word was n***, would that be okay? Certainly not to me," Clark said.
"Would you allow me to stop that."
Clark claimed to hate the term but again used the slur when citing the name of an Invercargill street gang.
Southland Business Chamber responds
In a statement, the Southland Business Chamber expressed its concern about Clark's "continued problematic conduct", notably at the UFBA Firefighter Challenge event.
Chief executive Sheree Carey said his behaviour breached the expected standard of conduct for elected leaders, jeopardised the reputation of Invercargill and should not be tolerated.
"Despite mayor Clark's health challenges and his subsequent apology, the recurring nature of these incidents indicates a critical need for systemic change within our city's leadership. The chamber firmly believes that Invercargill deserves leadership that acts with integrity and respects the dignity of all individuals," she said.
"Given the repeated nature of these incidents and the unwillingness of mayor Clark to adapt his behaviour despite previous feedback, the chamber believes that the most responsible course of action would be for mayor Clark to step aside."
The troubling behaviour included the use of racially and sexually insensitive language at an Arts Foundation tour and on national television, the chamber said.
Given Clark's admission he had a medical condition that was affecting his ability to perform his duties to the expected standard that could persist for years, his resignation could be a crucial step in protecting the city's reputation, the group said.
Invercargill City Council said Clark did not wish to comment ahead of Friday's meeting.